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About the Backup Retention Policy and the Fast Recovery Area

Spacc management in the fast recovery arca is govemed by a backup retention policy. A retention policy determines when files are obsolete, meaning that they arc no longcr necded to meet your data recovery objectives.

Retention policics can be bascd on rcdundancy of backups or on a recovery window (pericxl of time).

When using a policy based on rcdundancy, you specify how many fuli or level 0 backups of each data file and control file that RMAN keeps. If the number of fuli or Sec Also:

■"Planning Space Usage and Location for the Fast Recovcry Arca" on page 9-6

■"Configuring the Fast Recovcry Area" on page 9-10 Configuring Your Database for Basic Backup and Recovery Performing Backup and Recovery 9-7

level 0 backups for a specific data file or control file exceeds the rcdundancy setting, then RMAN considers the extra backups as obsolete.

When using a recovery policy based on a period of time (or window), you specify a time intcrval in days. Files are obsolete only when they are no longcr needcd for completc rccovery or point-in-time recovcry to a system changc number (SCN) within the window. Thcrefore, a recovery retention policy based on a window' is rccommcndcd.

The default retention policy is a rcdundancy of 1. Evcn after files in the fast recovery area are obsolete. they are typically not deleted until space is needcd for new files. If spacc permits, files rccently movcd to tapc remain on disk to avoid restoring them from tape for a recovery. The automatic deletion of obsolete files and files moved to tape from the fast recovery area makes it a convenient archiving destination. Other destinations require manuał deletion of logs.